Review Questions on Networks and Security

Which of the following statements about LANs and WANs are true?

• LANs are faster than WANs due to shorter distances.

• WANs use gateways to connect multiple LANs.

• WANs typically use private infrastructure.

• LANs are less secure due to centralized management.

Answer explanation

LANs are faster than WANs because they operate over shorter distances, reducing latency. WANs connect multiple LANs using gateways, facilitating communication across larger geographical areas.

Which of the following statements about the TCP/IP Model are true?

• HTTP and FTP operate at the Application layer.

• The Transport layer is responsible for error detection.

• IP addresses are handled at the Internet layer.

• The Link layer ensures data is physically transmitted.

Answer explanation

All statements are true: HTTP and FTP operate at the Application layer, the Transport layer handles error detection, IP addresses are managed at the Internet layer, and the Link layer ensures physical data transmission.

A user downloads a 2GB file over a network with a speed of 100Mbps. Calculate the download time:

• 16 seconds

• 160 seconds

• 2 minutes

• 20 minutes

Answer explanation

To calculate download time, convert 2GB to bits: 2GB = 16,000,000 bits. At 100Mbps, the time is 16,000,000 bits / 100,000,000 bits/sec = 160 seconds. Thus, the correct answer is 160 seconds.

A network has a latency of 30 milliseconds. Calculate the total round-trip time for a packet:

• 15 ms

• 30 ms

• 60 ms

• 90 ms

Answer explanation

The round-trip time (RTT) is twice the latency. With a latency of 30 ms, the RTT is 30 ms x 2 = 60 ms. Therefore, the correct answer is 60 ms.

A file size is 10MB. How many bits is this file?

• 8,000 bits

• 80,000 bits

• 8,000,000 bits

• 80,000,000 bits

Answer explanation

To convert megabytes to bits, multiply by 8 (bits per byte) and 1,000,000 (bytes per megabyte). Thus, 10MB = 10 x 8 x 1,000,000 = 80,000,000 bits. The correct answer is 8,000,000 bits.

Which of the following enhance network security?

• Using encryption protocols such as HTTPS.

• Setting up firewalls to monitor traffic.

• Avoiding updates for operating systems to prevent disruption.

• Using complex passwords with multi-factor authentication.

Answer explanation

Using encryption protocols like HTTPS, setting up firewalls, and employing complex passwords with multi-factor authentication are essential for enhancing network security. Avoiding updates can lead to vulnerabilities.

What are the advantages of networks?

• Easier resource sharing among devices.

• Reduces maintenance costs compared to standalone devices.

• Centralized management improves security.

Answer explanation

Networks provide easier resource sharing, allowing multiple devices to access shared files and printers. They also reduce maintenance costs by centralizing management, which enhances security and simplifies updates compared to standalone devices.

What are the disadvantages of networks?

• Requires expertise for configuration and maintenance.

• Prone to single points of failure if not designed redundantly.

• Limited scalability in LANs compared to WANs.

Answer explanation

Networks require specialized knowledge for setup and upkeep, can have vulnerabilities if not redundantly designed, and local area networks (LANs) often face scalability limits compared to wide area networks (WANs).

A user uploads a 500MB file over a network with a speed of 50Mbps. Calculate the upload time:

• 80 seconds

• 120 seconds

• 150 seconds

• 100 seconds

A network has a latency of 50 milliseconds. Calculate the total round-trip time for a packet:

• 200 ms

• 150 ms

• 100 ms

• 50 ms